Method and apparatus for cutting into sections the castings produced by a continuous rotary casting machine

ABSTRACT

Method and apparatus for cutting into sections a metal casting being continuously withdrawn from a rotary continuous casting machine by utilizing a rotary saw which advances parallel to the casting and is biased against the casting so as to produce an annular cut of increasing depth until the section is severed.

United States Patent Peytavin et al.

[ Sept. 17, 1974 Robert 164/263 METHOD AND APPARATUS FOR CUTTING 2,752,648 7/ 1956 INTO SECTIONS THE CASTINGS 2,372,733 12/1956 Thornberg 82/53.1 X PRODUCED BY A CONTINUOUS ROTARY 513 :3212 2/1961 Eddy 82/47 X /l964 Ball 164/70 CASTING MACHINE 3,157,079 11 1964 Harper 82/47 [75] Inventors: Pierre Peytavin, Neuilly-sur-Seine; A; g f 27 avls Lwls, Babel Smgny B018 both 3,310,855 3 1967 Ol'lOll 212 531 x of France 3,453,912 7 1969 Shal'cr 82/47 Assignee; Societe Civile dEtudes de 3,487,876 l/l970 BUCCl l64/263 Centrifugation Paris, France 3,612,148 10/1971 Waldschnudt 164/70 [22] F1 d J 31 1972 3,766,963 10/1973 Rossr 164/89 1 e an.

[21] Appl' 222080 Primary ExaminerHarrison L. l'linson Attorney, Agent, or FirmBrisebois & Kruger [30] Foreign Application Priority Data Feb. 5, 1971 France 7103953 [57] ABSTRACT [52] US. Cl 82/47,'82/53.1, 164/70,

164/282 Method and apparatus for cutting into sections a B23) 1/00, B231) 37/ 00, 322d 23/00 metal casting being continuously withdrawn from a ro- [58] F'eld of Search 82/47 53-1; 164/70 tary continuous casting machine by utilizing a rotary 164/89, 282 saw which advances parallel to the casting and is biased against the casting so as to produce an annular [56] References C'ted cut of increasing depth until the section is severed.

UNITED STATES PATENTS 2,350,975 6/1944 Rodder et al. 82/53.1 X 3 Claims, 5 Drawing Figures "/7 fr 11$ 1\ 20 I 1 X L f: p 3 J\ \j '1': HI 1; I\'\\\ \1 1 J9 T II I}. I g

\K 1 H 1.9& L o 75 l---- .l f I l I 1 7/)? 5 1 I 13 li T I t 11 11 1 '1 1' I 7 v I m 15 7 12 1/ 10 1 PAIENIEB sir 1 71914 sum 1 or 5 1 gmmmsm 11m SHET 2 OF 5 YIII'IIIIII METHOD AND APPARATUS FOR CUTTING INTO SECTIONS THE CASTINGS PRODUCED BY A CONTINUOUS ROTARY CASTING MACHINE This invention relates to a new method and apparatus for cutting into sections castings produced by a continuous rotary casting process. The method and apparatus according to the invention may be applied to all continuous rotary casting processes, but are particularly adapted for cutting into sections those vertical castings produced by a rotating vertical mold supplied with liquid steel.

It is well known that, during the continuous rotary casting of metals, liquid metal is poured into a rotating mold and the solidifed casting is extracted from this mold by extracting rollers, after which the resulting circular casting is cut into sections.

Heretofore this has been done by means of oxygen torches, said torches being mounted on a carriage which travels at the speed of the casting during the cutting operation. Such devices are complex in nature and produce casting sections having irregular end Portions, the structure of which differs from that of the rest of the casting.

In most applications, the sections of the casting cut off in this manner must be again cut off before use in order to eliminate the end portions of the sections. This additional operation results in a loss of material, a loss of time, and an increase in price which is by no means negligible.

On the other hand, in certain continuous non-rotary casting processes, cutting saws have already been .used. The use of saws makes it possible to obtain end portions of better quality, but the operation of cutting with a saw is time-consuming, especially when the castings are of substantial diameter, and in the case of relatively large castings it is necessary to use relatively large and especially expensive saws as well as high power.

The invention is intended to provide a process of cutting continuously rotating castings into sections which makes it possible to cut the castings at a high speed while producing smooth ends without consuming large amounts of power. As previously indicated, the invention is particularly useful in the case of the continuous rotary vertical casting of steel castings of high quality since it permits rapid cutting of the .casting, which is important in view of the relatively high extraction speed, and makes-it possible to produce-sections which are directly usable, for example, in manufacturing tubes of high quality.

' It is accordingly an object .of theinvention to provide a process of cutting rotating metallic castings made by a continuous rotating process into sections, which method is characterized by the fact that the cutting is carried out at high temperature "by associating with the rotating mold a rotating saw, whichpreferably turns in a direction opposite to the direction of rotation of the casting and cuts toward the center of the casting, said saw being driven in thedirection of extraction of the casting in synchronism with the rate of extraction of .the casting.

' As a consequence, only a small'number of. saw teeth are simultaneously in contact with the casting so that an extremely rapid'cutting is permitted under-the most favorable conditions. Moreover, the movement of the saw toward thecenter of the casting is at most equal'to the radius of the casting if the latter is solid, or to the thickness of the casting if it is tubular. In addition, the removal of fragments is very easy and there is no risk of jamming clue to fragments in the cut.

In accordance with one characteristic of the invention the temperature of the casting during cutting, in the case of steel, is preferably between 900 and l,l00 C. This temperature naturally varies between the outside and the inside of the casting.

In a surprising manner, end surfaces are obtained which are extremely smooth and flat despite the high temperature of the metal in the zone being sawed. It has even been found that the end surface of the section remains smooth and flat when the metal inside the casting in the zone being cut is still plastic or even fluid, whereas in the processes according to the prior art it is not possible to avoid deformation of the hot metal in the section.

This particularly advantageous property results from the fact that, as a consequence of the invention, the saw is rapidly cooled so that the saw cools the surface of the section of the casting during the cutting and thus prevents deformation of the metal. It is consequently'possible to carry out the cutting at higher temperatures than in the prior art, which still further increases the rapidity of cutting. In a preferred embodiment of the invention particularly applicable to castings produced by continuous rotary vertical casting machines, the casting is held firmly upstream of the saw mounting so as to prevent any axial displacement with respect to the saw, the rotary and translational movement of the casting being of course produced in the customary manner.

In the case of continuous vertical casting, force must be exerted on the portion of the casting being cut from the same side of the axis of the casting as the saw, in order to .keep the lips of the transverse cut being made by the saw constantly open.

It is also an object of the present invention to provide apparatus for carrying out this process characterized by the fact that it comprises a rotating saw mounted on a framework provided with means for driving it in the direction in which the casting is being extracted synchronously with that extraction, said saw being mounted on said frame by means which is movable on said frame in a plane transverse to the direction of displacement of said frame, said movable means being subjected, during the displacement of the saw, to a pressure in the direction of the axis of the casting.

The movable means preferably consists of an arm or lever .mounted to pivot aboutan axisparallel to the axis of extraction of. the casting and biased in the direction of the axis of said casting by suitable means, such as a pivotally mounted hydraulic cylinder.

However, this movable means may also consist of a slide mounted for translational movement transverse to the direction of the axis of the casting.

In accordance with a particularly valuable embodiment of the invention, the framework supporting the movablemeans is attached to the non-rotating part of a vise having rotating jaws which grip the casting ata short distance upstream of the saw in order to ensure synchronous movement of said frame with the casting in the direction of extraction of thecasting. Suitable means,-preferably hydraulic, are provided to returnthis frame, as well as the vise, in the opposite direction, once a cut has been completed andthe jaws of the vise have been released.

The vise which is attached to the frame which supports the saw may advantageously have two opposed jaws, the movement of which toward the casting is symmetrically produced by a device comprising, for example, two toothed sectors, one of which is in engagement with the other, and both of which are connected to means such as parallelogram linkage which transmits the rotary motion of these toothed sectors to said jaws to move them toward or away from the axis of the casting. These jaws, as well as the means for moving them, are supported by a rotary member turning in the relatively stationary part of the vise.

Advantageously the stationary part of the vise, and consequently the frame of the saw, are returned in the opposite direction to that of extraction by means of hydraulic cylinders.

Other advantages and characteristics of the invention will appear from a reading of the following description, given purely by way of example, with reference to the accompanying drawings in which:

FIG. 1 is a top plan view of a sawing device according to the invention, with the vise omitted;

FIG. 2 is-a cross-sectional view taken along the line ll-Il OF FIG. 1;

FIG. 3 is a cross-sectional view taken along the line Ill-III of FIG. 1;

FIG. 4 is a top plan view of the vise which is associated with the apparatus of FIG. 1; and

FIG. 5 is an axial sectional view taken through the vise of FIG. 4.

Referring now to FIGS. 1 to 3, FIGS. 1 and 2 show a solid round vertical steel casting 1 produced by a rotating vertical continuous casting mold and extracted from this mold by extracting rollers not shown. The vertical casting 1 is thus translated downwardly in the direction of the arrow F and rotated about its vertical axis in the direction of the arrow g. Beneath the extracting rollers, not shown, the casting 1 is gripped by a rotating vise, which will be described in detail in connection with FIGS. 4 and 5, and which is located in a cylindrical casing 2, the lower wall 3 of which is supported, for example, by flaps 4 pivotally mounted on a plate 5 which is substantially horizontally mounted on the frame 6.

This frame supports two vertical hydraulic cylinders 7, the piston rods of which project from the top of these cylinders and are attached to the stationary structure of the continuous casting'machine. In this manner, due to the hydraulic cylinder 7, the frame 6 is vertically displaceable in the direction of the arrow F to follow the casting downward during the sawing operation and then rise again in the opposite direction, after the cut has been completed, to the level of a new part of the casting to be cut.

The frame 6 is mounted on a movable arm or lever 8 adapted to swing in a horizontal plane. For this purpose the lever 8 is, for example, fixed to a post 9 which is mounted on arms 10 to swing about a vertical shaft 11 which is itself supported by suitable brackets on a vertical member 12 mounted on the frame 6. The movable lever 8 may thus pivot about the shaft ll. The pivotal movement of the movable lever 8 in the direction of the arrow h which causes it to approach the axis of the casting l, and in the opposite direction, is produced by a double-acting hydraulic cylinder 13 pivotally attached at 15 by an arm 14 to the frame 6. The free end 16 of the rod of the cylinder 13 is pivotally attached to the lever 8.

The lever 8 supports an electric motor 17 the upper end of the vertical drive shaft of which supports, through suitable mounting means 18, a circular saw 19, which consequently rotates in a horizontal plane. The direction of rotation of the circular saw is indicated by the arrow 1'. The lever 8 also preferably supports a protective casting 20 positioned around the saw 19 and comprising a gutter 21 for the evacuation of the scraps produced during sawing.

The device also comprises, supported on the plate 3, a sleeve 22 through which the casting 1 passes, and having at the level of the circular saw 19 a semi-circular slot 23.

The apparatus operates as follows:

When the frame 6 is located in its upper position by the hydraulic cylinder 7, the jaws of the vise rotating in the casing 2 grip the casting 1 at the moment at which the part of the casting to be cut reaches the level of the semi-circular opening 23. From this moment, due to the action of the jaws of the rotating vise, the frame 6 is driven downwardly in the direction of the arrow F, by the casting itself, which is driven by extraction rollers, not shown. Sawing may then commence. For this purpose, the piston of the hydraulic cylinder 13 is advanced and withdrawn in the direction of the arrow h, with the arm 8 which supports the saw 19 being rotated in the direction of the arrow 1' opposite to the one indicated by the arrow g, by the motor 17. Saw 19 comes into contact with the outer wall of the casting 1 with which it is translated in the direction of the arrow F, and begins to cut the casting. Since the casting is rotating in a direction opposite to the one in which the saw rotates, the saw makes a circular cut in it. It will be readily appreciated that only a few teeth on the saw 19 are simultaneously in engagement with the casting at the bottom of this cut. In this way the casting may be sawed rapidly without any need for imparting a very large rotative force from the motor 17 to the saw 19. Moreover, as a consequence of the process according to the invention, the saw is very rapidly cooled because only a few teeth at most simultaneously engage the casting. If necessary the cooling of the saw may be accelerated by suitable jets of water. This results in ready evacuation of the scraps without risk of jamming. When the saw 19 reaches the axis of the casting in the position shown in broken lines at 19a, the cut made by the saw in the casting 1 extends completely through the casting and a section thereof is detached to fall downwardly in the direction of the arrow F. The section which has been cut off is then removed by suitable means such as a swinging cradle.

By way of example, a casting such as 1, made of steel, about mm in diameter, having a temperature be tween 900 and 1,080 C, may be cut rapidly by a saw 660 mm in diameter rotating at 3,000 rpm driven by a motor 17 of 20 horsepower.

The force exerted by the hydraulic cylinder 13 is from 200 to 300 kg. The cutting time is about l5 seconds, which is substantially less than the cutting time for a casting of the same size which is not being rotated,

' when cut by devices heretofore known.

The cutting process according to the invention has the additional advantage that the section of the casting which is being cut off is always attached to the upper part of the casting at the level of the slot 23 by a sub- 5. stantially circular section which is coaxial with the casting which has not been cut off. In this way, the section being cut off by the saw has very little tendency to swing away from the axis of the remainder of the casting, which is particularly advantageous at high speeds of rotation. Moreover, the saw 19 advances in the circular cut in the casting without being pinched between the upper and lower'edges of the cut. It is, however, possible, in addition, to utilize a suitable abutment 24 to exert a force in the direction of the arrow j on the section of the casting being cut in order to hold the part of the cut in which the saw is engaged open.

Turning now to FIGS. 4 and 5, as will be seen on FIG. 5, the upper wall 25 of the casing 2 supports a vertical sleeve 26 in which a roller bearing 27 is mounted. This bearing rotatably supports a rotating member 28 comprising a flange projecting from an elongated internal sleeve 29, through which the casting 1 passes. At the upper end of the flanged member 28 are radial holes 30 communicating with vertical ducts 31. The holes 30 are positioned at the level of a circular groove 32 in the internal wall of the sleeve 26, which groove is connected to an opening 33. Sealing members 34 are provided between the stationary sleeve 26 and the rotary member 28 to provide a seal at the level of the circular groove 32. In this manner it is possible to introduce into the ducts 31 a pressure fluid supplied through the hole 33. This pressure fluid, for example compressed air, is distributed by the ducts 31 to ducts (not shown) in the movable means supported by the lower horizontal flange of the rotating member 28. The member 28 is preferably rotated by a motor not shown through a ring gear 35 carried on the periphery of the horizontal flange of the member 28.

As shown on FIGS. 4 and 5, the rotatable member 28 supports movable means comprising two jaws 36 positioned symmetrically with respect to the vertical axis of the casting 1. Each of these jaws 36 is pivotally attached by levers 37, 38, respectively, to pivot means 37a, 38a, carried by vertical tabs welded to the lower surface of the horizontal flange of the member 28. The jaws 36 are pivotally attached to the levers 37 and 38 by pivot means 37b, 38b, so that these jaws 36 are capable of being brought together or separated from the axis of the casting 1 while kept constantly horizontal by a parallelogram linkage, the arms 37a, 37b, and 38a, 38b being equal in length. In order to ensure symmetrical actuation of the two jaws 36 on opposite sides of the casting 1 at least two ofthe levers 38 engage each other through toothed sectors 39.

The gripping and release movements of the jaws may advantageously be produced by two hydraulic jacks 40, which are mounted head to foot. The cylinder of each jack is attached at 41 to one of two pins 42 passing through the jaws 36, and the end 43 of its piston rod is pivotally attached to the other pin 42. It will be seen that, in this manner, by actuating the hydraulic cylinders 40, the jaws 36 may be either brought together or separated, with symmetrical movement thereof assured by the toothed sectors 39.

Advantageously, the internal sleeve 29 extends to the bottom of the casing 2 so that it is gripped at four points, as may be seen on F IG. 4, so as to permit the introduction of the heads of the jaws 36 which grip the casting. I v

The fact that the casting is gripped by the jaws 36 at a very small distance above the saw 19 while sawingtakes place improves the conditions under which the saw operates.

While only a single embodiment of the invention has been described, it will be appreciated that this may be modified as to detail without thereby departing from the basic principles of the invention as defined by the following claims. In particular, it is obvious that the rotating vise may be used to attach to the rotating casting a cutting device different from the particular saw hereinbefore described.

What is claimed is:

1. Method of cutting a solid rotating steel casting being extracted at high temperature from a rotating mould into sections by using a rotating saw, which method comprises the step of gripping said casting upstream of the position of said saw by means which prevents any axial displacement of said casting with respect to said saw while translating said saw in the direction in which said casting is being extracted, and the step of urging said rotating saw toward the center of edges of the cut being made by said saw in said casting. 

1. Method of cutting a solid rotating steel casting being extracted at high temperature from a rotating mould into sections by using a rotating saw, which method comprises the step of gripping said casting upstream of the position of said saw by means which prevents any axial displacement of said casting with respect to said saw while translating said saw in the direction in which said casting is being extracted, and the step of urging said rotating saw toward the center of said casting in a zone of said casting in which its outer temperature lies between 900* and 1,100* C.
 2. Method as claimed in claim 1, comprising the step of rotating said saw in a direction opposite to the direction of rotation of said casting.
 3. Method as claimed in claim 1 wherein said casting rotates about a vertical axis, further comprising the step of exerting a force on the section of said casting being cut, in the direction of movement of said saw toward the axis of said casting to hold constantly open the edges of the cut being made by said saw in said casting. 